Pump



E. J. SVENSON y Feb. 8, 1944. v

, PUMP original Filed Marh 3o. 193s 4 sheets-sheet 1 INVENTOR.

Feb. 8, 1944. E. .l. svx-:NsoN

PUMP

originai Filed March so, 195s -4 sheets-sheet 2 ma Q ws,

www

y Feb. 8, 1944. E. J. svraNs'oN PUMP Original Filed March so, 1955 4 Sheets-sheet s Feb. 8, 1944.

E. J. SVENSON PUMP Original Filed March 50, 1936 4 sheets-sheet '4 mwwmvm INVENTOR.

y Parente-Fea a, i944 stares Para PUMP,

Ernest J. Svenson, Rockford, lili., assigner, by mesne assignments, to Odin Corporation, Chicago, lll., a corporation of Illinois Original application'-March 30, 1936, Serial No.

71,754. Divided and this application January 22, 1.941, Sml N0. 375,50@

' ..21 claims.

This invention relates to pumping mechanisms, and more particularly to pumps of the variable displacement type.

It is an object ofthe invention to provide a variable displacement pump having incorporated therein improved means for adjusting the pump displacement, which means is readily operable throughout a. given range of displacement adjustment, and operable in any adjusted position to accurately and positively maintain the pumping mechanism at the `desired setting.

More specifically stated, it is an object of the invention to provide an improved eccentric type adjustment for variable displacement pumps and the like, the eccentric adJustment mechanism being operable to accurately position and maintain the pump displacement in any desired position within a given range of pump displacement adjustment. In accordance with the invention,

pendently operable pump displacement adjust-` ment means, at least oneof which is adjustably operable during the operation of the pump. To this end the invention contemplates the provision of a iii-st adjustment means adjustable to set @the pump to any suitable normal or desired rate of displacement within the pumping-range. and a second adjustment means operable while the pump is in operation to modify the pump displacement from such normal displacement to .another desired displacement which, for example, may be zero displacement.

Still another object ofthe invention is to provide improved means for inserting a valve housing or assembly into a pump body in a tight and leak-proof manner.

Various additional objects,v advantages and as er object of the invention is to provide, l

l in a variable displacement pump, two indea0V features of the invention will be apparent from the following specication, when taken in connection with` the accompanying drawings wherein certain preferred. embodiments of the invention Vare set forth for purposes of illustration. In the drawings, wherein like reference numerels refer to like parts throughout:

Fig. 1 is a partial, elevational view of a machine tool structure including a pumping mechanism constructed in accordance with the principles of the invention;

Fig. 2 is a diagrammatic view of the hydraulic circuit for the structure of Fig.,l, and including the pumping mechanism of the invention;

3 is a sectional View of the structure of Fig. l, taken on rthe line 3 3 thereof and more particularly illustrating .the pump structure;

Fig. 4 is a view of a pump structure similar to that illustrated in Fig. 3, but incorporating auxiliary mechanism, a second adiustment means, to vary the pump displacement;

' Fig. 5 is a transverse, sectional view of the pump mechanism of Fig. 4, takenl substantially along the line 5 5 thereof;

Fig. 6 is a transverse, sectional view of the.

Diesel motors;

1 Fig. 9 is an elevational view, shown partly in l section, of mechanism for controlling the second adjustment means of the pump of Fig. 4, said view being taken substantially along the line 9-9 or Fig. 10; and

Fig'. 10 'is a front, elevational view of the displacement control device shown in Fig. 9, a portion of the housing thereof being broken away to disclose 'parts otherwise hidden.

In the drawings, the pump structure of the invention has been shown-in association with a machine tool structure which it is adapted to Aoperate and propel, as the pump.l due to its accuracy and positive. and accurate adjustment characteristics, is well adapted for machine tool Work. It is to be understood, however, that the pump, and its adjustment mechanisms; 'may be adapted for various operations and uses. 'Ihis application is a division of my copending application.

serial No.; 71,754.V med Maren ao. 1936, new issued a as Patent No. 2,268,829, dated December 23, 1941,

and entitled Metal working apparatus.

Referring more particularly to the drawings, and rst to Figs. 1, 2 and 3 thereof, the machine .tool structure disclosed comprises a machine tool head unit designated generally by the .numeral 40' slidably mounted on ways 48, Fig. 1, carried by a main machine supporting frame or base 42,

and adapted to carry a series of rotatable tool supporting spindles l2. A uid motor indicated generally by the reference numeral H8, Figs. 1v

and 2, and comprising a piston H8 and pi'ston rod |28 secured to the main frame 42 and a cylinder ||8 carried by the head frame `unit 40 is provided for propelling the head frame along the ways 48. Pumping means such as a rapid traverse pump |38 and a plunger pump |88. Fig. 3, the latter pump forming the subject matter of ,the

present invention, are provided in cooperation with suitable valve means, such as indicated by the reference numeral 288, Figs. l and 2, for controlling the delivery of iluid to the hydraulic motor iid.

The .head frame 4|) carries a suitable prime mover such as an electric motor 88, Fig. 1. for

driving the tool spindles H8 and the pumps. To this 'end the electric motor 50 carriers a pulley 84 adapted, by means oi belts 88, to drive a pulley 82 carried bya main drive shaft 5d. Thisy drive shaft drives the spindles H2 and is also provided with a gear 88, Figs. 1 and 3, adapted to.coop erate with and drive a gear |38 secured to a pump asunto |12 communicating with valves |81 beingsealed by the pump .|54.

In order to provide a variable eccentric or cam driving mechanism for the pistons |58 having a 6 minimum number of parts, I prefer to eccentrically machine a studor pin |14 directly on the pump variator' drive shaft |40. A driving ring v or bearing structure |18 includes an eccentric inner race member |18, which ismounted upon .the eccentric crank pin |14.

An outer race |80 and the ball bearings associate\d\therewith are a commercial standard product, the only specially machined part being the inner race member |18. v

It will thus be apparent that by rotating the .inner race member |18 with respect to the crank pin |14, a variation in piston stroke is obtained. To effect this relative rotation of the inner race |18 and the pin |14, I employ a sleeve |82 having a suitable coupling with the inner race |18, such as a pin and slot arrangement |84. A clamp stem |88 serves to support a clamping nut |88. To

ing the, pump variator drive shaft |40 in proper.

drive shaft |88, one end of which is adapted to drive the rapid traverse pump |84, and the other end of which is.y adapted to drive the plunger pump |38-forming the subject matter oi' this invention. Pump drive lshaft |40 is carried byl ball bearings |42 and |48.

Referring more particularly to the pump |88, its construction is in general similar'to that disclosed in my copending application, Serial No.

. 684,677, filed August 11, 1933 and now issued as Patent No. 2,215,257, dated September 17,1940.

More speciflcallyit consists' of a pumpbody or housing |54 suitably secured to 'the head frame casting at |58, Fig. 3. as'by means of screws (not shown). The pump |38 includes a suitable numposltion, a retainer or ring |98 is employed, said retainer being secured in position by means of screws |98.

A detailed explanation of thefunctioning of the pump |38 is not necessary, and it will suilice driving mechanism ber of pistons |58, ve in the present embodiment, and these'pistons are reciprocably mounted within the pump body |58. I provide an inlet y valve assembly |80 for each piston |58, and an outlet valve assembly |82 for each of said pistons, there being live inlet and ive outlet assemblies in the embodiment shown. A unitary valvehousing |84 is provided with' seats for ball valve members |88 and |81, as clearly shown in Fig. 3. In manufacturing this housing |54 did not give satisfactory results, due

to the shearing action of the pump body. when .the valve housing was being inserted. 'I'he absence of a tight nt presented the problem oiv fluid leakage. I therefore prefer to first subject 'the valve housing |84 to a shrink 'process in "dry1ce or liquid air," and if desired, also to subject pump body |54 to expansion in a heated body or oil. I then insert the shrunken or contracted valve housing |84 into the expanded pump housing |54, and when the temperature oi' municating with the valves |88, an outlet groove structure, I found that pressing the unitary valve housing |84 into the pump.

to state that the pressure of fluid within the intake groove |10 opens each complementary ball valve |88 in turn, and causes the companion piston |58 to follow the movement of the eccentric |18. When said piston reaches the limit of its downward movement, said ball valve |88 closes and uid is discharged under pressure as the piston is urged outwardly through its associated outlet vllve |51.' An auxiliary pump such as the pump indicated at |58, Fig. 3, or other suitable means, may be employed to maintain a Isuitable pressure"in the intake groove v|||l.r A,

The plunger. pump |38, together with rapid traverse pump |34, is adapted to propel the fluid motor ||4 through the control of the valve mechanism 208, as previously stated, the circuits being diagrammatically indicated in Fig. 2. However, inasmuch as the present -invention more particularlyconcerns the pump structure, a detailed.v description of the valves, fluid circuits, and the like is lbelieved to be here unnecessary. A full description of these mechanisms appears `in lmy aforesaid application, Serial No. 71,754, of

which the present application is a division.

As previously stated, my invention as applied to the pump |38 is not limited to a machine tool structure. For example,` the driving arrange- .ment and pump structure is designed for Diesel motor (not shown).

application to Diesel motors or the like. In Fig. 8 I have disclosed the lmanner in which the outlet valve assembly |82 could be slightly modified by eliminating the groove |12 and providing a passage 204, which serves to direct fluid under pressure through a suitable channel or conduit 208, which may be connected with a cylider of 'the ball valve mechanism just described may serve to properly inject uid under pressure-into any suitable device such as the cylinder of a con..

By removing a cover In other words, the

member'498 (Figs. 9 and 10) be governed by the disposition of the ball valves and the rotation. of the eccentric driving mechanism |16. Obviously the number of pistons will conform with the number of cylinders or other devices into which iiuid is to be injected.

One of .the most diicult problems to solve in connection with the design of iiuid control mech- A.l

such as hydraulic transmissions, where accuracy and variable displacement are required, is that of providing a practical, eiiicient control of the variable displacement of the pump. Many attempts have been made to solve this problem and, to my knowledge, none of these attempts has been wholly successful. In conventional hy draulic systems with which I am familiar positive coaction between elements designed to control pump displacement has not been obtained,

and as a result the displacement control has not satisfied the demand in the industry fora simple, practical control arrangement. In fact, hydraullc controls should be designed with the idea of enabling even those unskilled in the art to understand the function of such controls.

I have previously explained the functioning of the simple eccentric driving mechanism |16 disclosed in Fig. 3, which includes the crank pin |14 and eccentric driving ring |18. That arrangement satisfies certain requirements in the iield, but certain environments require further adjustment of the piston stroke. I accomplish this by incorporating within the pump housing-` |54 a simple cam device 468 (see particularly Figs. 4 to 7 inclusive). 'I'his cam device 468 includes an annular body portion 418 and a plurality of lateral cam elements 412 projecting laterally of the body 818.

These cam elements 412, which may be individually shaped to the adjustment requirements of each associated piston, are companion to pivoted pump fingers 414, which fingers are interd between the inner ends, of the pistons |58 and the periphery of the ring |88 of the eccentric driving mechanism |16. For a moredetailed description and explantion of the pivoted lingers 414, reference is made to my copending application, Serial No. 548,569, led July 3, 1931, and my i placement of the pump.` The cam structure 468 55 comprising the cam disc 418 may be rotated" within limits determined by the adjustablestop Stop pins 416 carried by the pump housing maintain the cam disc 818 in position to be rotated, as shown inl Figs. 4 and 6, while permitting the camdisc to bev disassembled by matching the pins 416 with the slots mechanism 468 is accomplished by rotating a gear segment 482, which meshes with complementary teeth provided along the periphery of the cam body 418, said segment being mounted upon a shaft 484. By shifting the cam device 888, the effectiveness of the cam elements 412 upon the ngers 414 and' consequently upon the pump pistons |58 may be varied.` Thus when the elements 412 are shifted to the extreme posimon from that disclosed in Figs. and 6, they do ventional motor employing fuel oil, for example, -motors commonly known in the trade as Diesel type motors, and the timing of said injection will mechanism |16 to function as previously described in connection with Fig. 3.

Obviously the limitation with respect to the range of stroke of the pistons |58, which is controlled by the camelements 412, will vary in accordance with the environment in which the device is to be employed.- I have found itv practical to select a maximum normal displacement in accordance with the circumstances under which the pump is to be used by adjusting the eccentric driving mechanism |16 and to vary from said normal displacement to a minimum displacement requirement by interrupting the movement of the lingers 414, as above described. I have found that better results in the propulsion of a hydraulic actuator-for example, the actuator |4- are obtained when the displacement in the lower ranges is controlled by the cam mechanism 468.

At extremely low displacement, or in other words,

relatively short piston strokes, leakage is reduced to a minimum, and material or metal expansion is also obviated. It should be understood that the number of pistons employed controls the practical range of variation which may be accomplished by controlling the linger movements. I have found it practical to select-a normal lpump displacement of half the piston stroke by adjusting the driving mechanism |16, and to employthe finger or cam control mechanism to vary the displacement from this half stroke point to zero when five pistons are employed. Obviously if the number of pistons is changed, this will vary the range over which the cam or finger control ma be used.

Any suitable means may be employed to adjust the cam mechanism 468, but referring to Figs. 9 and 10, it will be seen that I prefer to automatically shift the ca m mechanism through the agency of a hydraulic actuator designated generally by the numeral 486. This actuator is supplied with uid pressure through a passage 488 (Fig. l0), which pressure causes a piston 498 of the actuator 486 to shift to the left, the piston rod 492 of said actuator providing a rack which meshes with a gear segment 494. 'I'his gear segtent No. 1,989,118. When these cam elements .418 of the cam disc. The shifting of the cam v ,ment 494 is mounted on the shaft 484, which also carries the gear segment 482. Therefore,shift ing the piston 498 to the left (Fig. l0) causes the cam mechanism 468 to be adjusted. A spring 496 serves to shift the piston 498 to the right upon release of pressure within passage 488. An adjustable stop 498, which may be adjusted through the agency of a knurled head 588, serves to limit the forward movement of the piston 498.

A valve mechanism 582 serves to direct iiuid to the actuator from a suitable source such as the circulating uid of the rapid travse pump |34. The -valve 582 includes a valve piston 684, which carries an extension 586. This extension 586 isadapted to be operated by any suitable means, as for example by a dog 588 or the like suitably carried by the head frame 48 and adapted to engage the extension at a given point of movement of the head. A spring 5|8 urges the valve piston 584 outwardly, and a conduit or channel 5|2 at one extremity of the valve mechanism 582 connects with the channel 488. Fluid pressure is introduced to the valve through a port 5|4, which communicates with a longitudinot engage the fingers 414 and permit the passage 5|8 when the valve member 584 is shifted to the left. 'Ihus the shifting of the valve member 684 to the left in response to the engagement of the extension 686 with its operating means establishes communication of uid under pres- 4 sure with the right extremity of lthe hydraulic actuator 486, and thereby causes the shifting oi.' the piston 49u to the left. This shifting may be accomplished at any desirable point in the cycle of movement of the head. When valve Bill is permitted to return to the right, to the position of Fig. 10, valve passage Sia` is .brought into `communication with a drain passage El@ whereby to relieve the pressure within channel 488 permitting spring 49B to act to'return the piston 488.

From the foregoing it will be apparent that, when the eccentric driving mechanism H6 has been adjusted to cause the pump |36 to deliver iluid at a normal rate of displacement, the cam elements 472 are-not engaged bythe lingers 414. When a decrease in displacement is desired, which is determined by the position of the operating dog or the like for the extension 60S, the valve member 504 is shifted to the left, which causes -:fluid to be delivered to the right end of the hydraulic actuator 488, thereby causing a shifting o! the cam mechanismii and a consequent decrease in the iiuid displacement of the pump.

Obviously numerous modications and changes and discharging uid, cam driving means for' shifting said pistons, meansincluding a cam f member adapted to be functionally interposed between said cam driving means and said pistons for limiting the piston shifting effectiveness of said cam driving means, and means or shifting said cam member into interposed posi ion.

3. A` pump mechanism including a housing, shiftable pistons in said housing for receiving and discharging iiuid, cam driving means for shifting said pistons, shiftable members between said cam driving means and said pistons, and adjustable stop means for limiting the movement of said shiftablemembers toward the axis of said cam driving means to limit the piston shifting eilectiven'e of said cam driving means.

4..A pum mechanism including a housing,

ars-imac member and pin tor purposes of carriv adjustment, said shiftable members being pivotally mounted upon said housing.

6. Piston stroke controlling mechanism including an inner eccentrically apertured race member, an eccentric supporting pin therefor,

an outer concentricallyv apertured race member' encircling said inner race member, pivotal nngers engaging the outer race member, and means for relatively rotating said inner race member and pin for purposes oi' eccentric adjustment.

'7. A pump mechanism comprising a housing,

a shiftable piston associated with the housing' for receiving and discharging fluid, cam driving means for shifting said piston, said cam driving means including an eccentric driving pin and an eccentrically formed ring member mounted on said pin, a member shiitably supported upon the housing' interposed between the piston and the ring member, and means for relatively rotating said ring member and pin for purposes of cam adjustment.

8. Stroke controlling mechanism for shiftable elements and the like comprising a housing, an eccentrically apertured ring member in the housing adapted to shift the shiftable element,

an eccentric supporting pin ior the ring member, a member shiftably supported upon the housing interposed between the element and the ring member, and meansI for'relatively rotating said pin and ring member for purposes of eccentric adjustment, whereby to vary the shifting movement imparted to said element.

9. Stroke controlling mechanism for shiftable elements and the like comprising cam driving means for shifting the shiftable element, adjustp ment means for varying the path of travel oi the cam driving means whereby to vary the degree of shifting movement imparted to said element, and ad tional adjustable means functionally interpose between said adjustable cam driving means and said element for limiting the element shifting eiectiveness of said cam driving means.

10. In a power driving mechanism including a member adapted to be reciprocated, driving means i'or reciprocating said member, adjustment means for the driving means to enable the driving means to reciprocate said member 'a selected distance of travel, and means associatedl with the driving means constructed and arranged to modify the limits of said distance of travel thereby imparting another and preselected traval of reciprocation to said member while maintaining said driving means in its adjusted shiftable pistons in said housing for receiving and discharging fluid, cam driving meansV for shifting said pistons, pivoted iingers between said cam driving means and said pistons, 'and adjustr able stop-means for limiting the movement of said pivoted fingers toward vthe axis of said cam driving means to limit the piston shifting eiectiv'eness of said cam driving means.l y

5. A pump mechanism including` a housing, shiftable pistons in said housing for receiving and discharging iiuid, cam driving means for shifting said pistons, said cam driving means including an eccentric driving pin, aneccentrically apertured inner race member mounted onsaid pin, a concentricaiiyapertured outer race member encircling said inner race member, shiftable members interposed between said outer race member and said pistons and bearing directly against said race member Vand said pistons,-and means for relatively 'rotatingsaid innerrace position. t

11. A pump mechanism including a housing, shiftable pistons in said housing for receiving and ldischarging uid, eccentrically Aoperable driving mechanism for shifting said pistons, means automatically operable 'during the operation of the pump for varying the piston shitting effectiveness of'said driving means, and manual adjustment means for controlling the limits of operation of the automatic means.

12. A variable displacement pump including a housing, shiftable pistons in said housing for receiving and discharging fluid, driving mechanism for imparting varying amounts of shifting movement to said pistons, manual adjustment means` for determining the maximum amount of movement imparted to the pistons b y the driving means, manual adjustment means for determining the minimum amount of 'movement .imparted to the pistons by the driving means, and'means `automatically operable dln'ingthe voperation 0! ing pin and an eccentrically formed ring member mounted `on said pin, and means for relatively rotating said ring member and pin to any position within their relative range of travel for purposes of eccentric adjustment, said last named means being arranged and adapted to rotate with the pin and ring member as a rotary unit during the operative functioning of the pump. 14;. A pump mechanism including a housing,v

shiftable pistons associated therewith for receiv ing and discharging nuid, cam driving means for shifting said pistons, said driving means including an eccentrically disposed driving pin and an l leccentrically formed ring member mounted on the pin, the amount of eccentricity or the pin and of the ring member being substantially equal, and adjustment means for relatively rotating the pin and ring member to any position within their relative range of travel -for purposes of eccentric adjustment whereby the pin and ring .member may be movedv from a position wherein their eccentricities neutralize eachother progressively to a position where the eccentricities `are additive to produce a maximum cam throw, said adjustment means being arranged and adapted to rotate with the pin and ring member as a rotary unit during the operative functioning of the pump.

15.A pump mechanism including a housing, shiftable pistons associated with the housing for receiving and discharging duid, vcam driving means for shifting said pistons, means for limiting the movement of the pistons. and means for moving said limiting means selectively to an operative position for limiting the movement of the pistons, and to an inoperative position wherein the full piston shifting` eiectiveness of the cam driving means is transmitted to the pistons.

16. A pump mechanism including a housing, shiftable pistons associated withthe housing for receiving and discharging iiuid, cam driving means for shifting said pistons, means for limiting the movement of the pistons, and means for moving said limiting means selectively to an operatively position for limiting the movement of the pistons, and to an inoperativeL position' wherein the full piston shifting effectiveness of the cam driving means is transmitted to the pistons, said means for moving the limiting means being operable during the operation of the pump.

17. A pump mechanism including a housing,

shiftable pistons associated with the housing for receiving and discharging nuid, 'cam drivingl means for shifting said pistons, means for adiusb.

of the cam driving means is transmitted to the pistons.

1,8. A pump mechanism including a housing, I

shiitable pistons associated with the housing for receiving and discharging uid, cam driving means for shifting said pistons, means for adjusting the throw of the cam driving means,

.means for limiting the movement of the pistons,

and means for moving said limiting means selectively to an operative position for limiting the movement of the pistons, and to an inoperative position wherein the full piston shifting eectiveness of the cam driving means is transmitted to the pistons, said means for moving the limiting means being operable during the operation of the pump.

19. A pump mechanism including a housing, shiftable pistons associated with the housing for receiving and discharging iiuid, cam driv ing means for shifting said pistons, means for limiting the movement of the pistons, means for moving said limiting means selectively to an operative position for limiting the movement of the pistons, and to an inoperative position wherein the yfull piston shifting effectiveness ot the cam driving means is transmitted to the pistons, and means for adjusting the amount of limiting eiectiveness ofthe limiting means when in operative position.

20. A pump mechanism including a. housing shiftable pistons associated with the housing tor receiving and` discharging iiuid, cam driving means for shifting said pistons, means for ad- Justing the throw of the cam driving means,

means for -limiting the movement of the pistons. and means for moving said limiting means selectively to an operative position for limiting the movement of the pistons and to an inoperative position wherein the full movement of the cam driving means is transmitted to the pistons, and means for adjusting the amount o! limiting effectiveness of the limiting means when in operativeposition.

21. A pump mechanism including a housing, shiitable pistons associated with the housing for receiving and dischargingv duid, cam driving means for shifting said pistons, means for limlting the movement of the pistons, and uld operable means .operable while the pump is in operation for moving saidy limiting means selectively to an operative position for limiting the movement of the pistons, and to an inoperative position wherein the full piston shifting effectiveness of the cam driving means is transmitted to the pistons.

' ERNEST J. BVENSON. 

